句柄类，结构体中有一个指针，该指针指向一个结构，该结构的定义与其所有的成员函数的定义一同出现在实现文件，这样只要借口部分不改变，头文件就不需要变动，而实现部分可以按需要任意更改，完成后只需要对实现文件进行重新编译，然后重新连接到项目中。-Handle class, struct, a pointer to a pointer to a structure, with the definition of the structure with all the member functions defined in the implementation file, so as long as the excuse part does not change the header files do not need to change, but to achievepart can be arbitrarily changed, finished only need implementation file to be recompiled, and then reconnect to the project.